He was planting a tree. And, in a way, nurturing the seed of an idea: a shift in the American way of death - a departure from chemicals, concrete vaults and manicured plots.

Mann, cemetery president and CEO, was ceremoniously opening a 31/2-acre "natural" burial ground at the 1869 Lower Merion cemetery, where 100,000 people are buried, including a Titanic survivor and sculptor Alexander Stirling Calder.

No embalmed bodies will be allowed in this area, which has room for 400. Only untreated wood and biodegradable shrouds can be used.

Markers will be little more than fieldstones; Bringhurst Funeral Home, which is on site, will help families conduct at-home funerals and make caskets.

Each year, along with their dearly departed, Americans bury 827,060 gallons of embalming fluid and 30-plus million board feet of timber, according to the Green Burial Council, an advocacy and certification organization in New Mexico.

Its founder, Joe Sehee, says we bury enough steel to rebuild the Golden Gate Bridge, and enough concrete vaults - to keep the ground over graves from sinking, which makes maintenance easier - to pave a highway halfway across the United States.

"A lot of people don't want to feel like their last act is one of pollution," he said. "I don't think people have embraced conventional funeral options as much as tolerated them."

Now people are being buried in coffins made of wicker or bamboo. In Ecopods of recycled paper. Even in simple shrouds. A San Francisco company offers them in linen, silk and ethnic textiles.

Green burial sites even include forests, grasslands, and other natural areas - with the burial money helping to keep the land undeveloped.

Markers might be nonexistent, with GPS coordinates the only thing guiding loved ones to the spot.

Sehee founded the certifying group in 2005.

So far, the council has approved seven casket and urn companies, more than a dozen cemeteries, a couple of cremation-disposition programs, and nearly 200 funeral-service providers.

Though still just a tiny part of the $11 billion annual U.S. funeral industry, green burials and funerals are gaining ground, industry officials say, because of the growth of a broader green ethic.

"It's a great movement," said Ellen Wynn McBrayer, spokeswoman for the National Funeral Directors Association and a Georgia undertaker who is "heading in that direction" herself.

"Some religions, and some people, prefer ashes to ashes, dust to dust."

True, some are repulsed by the idea of not embalming. But in a 2007 AARP funeral survey, one-fifth of respondents said they were interested in something more eco-friendly.

"If you drive a Prius, live an environmentally conscious life and read Dwell magazine, you are not going to settle for the options offered at a traditional funeral home," said West Chester's Donna Larsen, with A Natural Undertaking, a resource center for home funerals.

At West Laurel Hill, people had been asking about green funerals, Mann said after the opening a week ago. "We took the position of, if people want to do it, we ought to figure out how to help them."

Indeed, green burials are also seen as one more way people are taking back hallowed rituals, loosely akin to outdoor weddings and birthing at home with a midwife.